Method of making attachment caps



G. B. BENANDER METHOD OF MAKING ATTAQHMENT GAPS Filed May a, 1937 2 Sheets-Sheet l m m F h n 00 I E Q eB 5t V i w s e wan 1 G W m.

N ONMFMM U mum JuEy 2, 1940., G. B. BENANDER METHOD OF MAKING ATTACHMENT CAPS Filed May 8, 1937 2 Sheets-Sheet 2 Inventor":

P, w m /M AW n n e P 8 4m Bat Wm i 9 G b I 1 I UNITED STATES Patented July 2, 1940 PATENT OFFICE I METHOD OF MAKING ATTACHMENT oAPs A George B. Benander, Yalesville, Conn., assignor to Monowatt Electric Corporation, Bridgeport, Gonn a corporation of Connecticut ApplicationMay 8,1937, Serial No. 141,584 1, Claim. (01. 18-59) The present invention relates to attachment.

caps such as are used for detachably connecting electrical conductors to convenience outlets, for

example. I I

One object of my invention is toprovide an improved cap which is simple in structure, durable and capable of being I manufactured I at low cost.

A further object of my invention is to provide an improved method and apparatus for use in manufacturing my improved caps.

For a consideration of what I believe to be novel and my invention, attention is directed to the following specification and the claims 13 appended thereto.

In the drawings, Fig. 1 is a perspective view of a press. used in the carrying out of my invention; Fig.2 is a detail perspective view of a part of the press shown in Fig. 1, illustrating one 20 step (in the manufacture of a cap; Fig. 3 is a I view similar to Fig. 2 showing the parts in a different position and illustrating a second step in carrying out the invention; Fig. 4 is a per spective view illustrating a further step in 25 carrying out the invention; Fig. 4 is anend viewof a part of the press; Fig. 5 is a detail sec tional view of a part of the pressshown' in Figs. 1 to 4; Fig. 6 is a sectional view of a com- 3 pleted cap; Fig. '7 is a face view of the" casing View of a completed cap; Fig. 9 is a sectional view of a modified form of cap; Fig. 10is a view similar to Fig. 9 showing a further modification; Fig. 11 is a perspective view of the upright shown 35 in Fig. 10, and Fig. 12 is a detail. view of another form ofupright.

\In; carrying out my invention, I first form a casing I, of suitable shape. having a passage 2 forelectrical conductors and a chamber 3fhaving shoulders 4 at its inner end. The walls 5 ofthe chamber 3 are spaced from each other a distance equal to the spacing of the uprights of standard attachment. caps. Surrounding the rim of the casing is a flange 5 Preferably, the

operation. However, WhileI now prefer to use a" molded rubber casing, I may, if found desirable, form the casing of some'other material,

. either a thermo-plastic or a thermo-setting material. i

I In the, present instance, .I have illustrated a cap; having a rectangular body portion 6; provided with around extension 1 through which thewire passes, However, thebody oi the, cap

rights. correctly in the chamber.

used in making the cap; Fig. 8is a perspective I to the-inner ends of the uprights.

casing is formed of rubber by a suitable molding,

setting substance.

-tirely through the cap and is enlarged at one end to form the chamber .3. I then mount in the chamber 3 a pair of uprights or contact prongs In to the inner ends of which the conductor wires II have been attached by suitable 5 means such as by soldering or welding. The uprights fit against the end walls of the chamher. as shown inFigs. 5 and 6 with their inner.

ends in engagementjwith shoulder 8 and are held firmly between the side walls of the chamher. The shoulders 4 serve to position the up- The projectionsformed on the inner ends of the uprights by the ends of the Wires and the solder fit in grooves 8 so that thetprongs can fit tightly I against the end walls of the chamber and stand straight. As shown in Figs. 5 and 6, the uprights lllhave notches w in their inner ends in which the ends li of the wires of the cord H are located and attached bysoldering, weldmg. or in other suitable manner, the wires being bent upon each side of the uprights adjacent the inner ends of the notches and fastened in this. position. This forms a convenient and satisfactory arrangementior attaching the wires Also, in the inner ends of the uprights are openings I2.

' After the wires have been attached to the inner ends of the uprights and the uprights have been positioned in the casing, the space in 40 chamber 3 between the uprights is filled with an insert comprising a moldable substance it which is put into the space in its uncured condition, after which it is cured or permitted to harden. By a moldable substance, I mean a substance which is capable of being compressed or flowed into the chamber and then hardened by curing with heat or by standing. I I may use either a thermo-plastic substance or a thermo- Preferably, I employ rubber as the substance i3, uncuredrubber being forced into the space by a suitable press and then cured while in the press. A portion of the moldable substance, such as uncured rubber, flows through 5% the openings i2 as shown in Fig. 6' and adheres to the end walls of chamber 3. Also, the substance adheres more or less firmly to the side taken by the cap body itself and not by the con nections with the uprights.

. A completed cap is shown in Fig. 8 and. as will be seen, I provide a cap which has a smooth unitary appearance and in which the uprights are firmly embedded in the materials forming the completed cap. As stated above, I employ preferably rubber for both the casing and the insert, and when rubber is employed the insert when vulcanized becomes well attached to the casing walls forming therewith a more or less integral structure.

In Fig. 9 is shown a modified construction wherein the cap casing it has smooth end walls, the grooves 3 as shown in Figs. 5., 6 and 7 being omitted. To make room for the projections I5 formed on the inner ends of the uprights it by the wires and solder, the inner ends of the uprights are bentinwardly as indicated at H. Otherwise the construction shown in Fig. 9 is the same as that shown in Figs. 5 to 8 inclusive.

In Figs. 10 and 11 is shown a modified form of upright it, the same comprising a strip of materialbent double and having the end of the wire i9 soldered between the two adjacent ends of the legs of the strip. With this construction, the two legs of the'strip may be entirely in engagement with each other or they may be bowed somewhat' as shown in Figs. 10 and 11 so as to provide an upright which is capable of being compressed so that it may make a yielding contact with the contact of the convenience outlet spaced apart to accommodate the wire end and solder.

For manufacturing caps embodying my invention, I provide, a press comprising a base plate 25 on which is mounted by means of bolts as a series of plates 21 having spaced notches in theirsides to form side and top opening recesses or cavities 28 of a contour to receive and hold a casing 5. Each cavity has a shoulder 44 to form support for a cap casing. Suitably hinged to the upper edgeof plates Ell as shown at 21 is a cover plate 29 having openings at, one for each recess 28, and located over the center of the recess. Between the rear edge of cover plate 29 and the top of the uppermost plate 21! is a spacing strip 38 which serves to space the underside of the cover plate from the top plate-2'! as indicated at St lhe width of this spacecorresponds with that of flange 5* on the rim of the cap casing. On each side of each open ing 38 (see Fig. 5) is a slot 3'! of a size to receive the outer end of :an upright. The cover 29 is adapted to rest onthe top of spacing strip 30 on its closed position and to be moved on its pivots 277 from closed position to open posltion as shown in Fig. 2 where it stands at right angles to plates 27. The cover isheld in closed .position by a pair of arms 32 pivotally mounted necessary merely to swing the arms 32 away from their positions over the cover, after which the cover may be readily opened. In the present instance, the cover is shown as being opened by a rod 3 5 attached-at one end to the end of an arm 3% fixed on the cover and at the other end to a suitable foot treadle. Slidably mounted on rodstfii'is a plunger bar 35 which carries a series of plungers 36, one for each cavity 28, the plungers being in line with the openings til. The plunger bar 35 is attached to the piston rod 31 of a hydraulic press, the piston of the press being located in cylinder38. ried on a cross plate 39 fixed on the upper ends of rod 33. At M is indicated a suitable valve for controlling the admission of compressed air or other operating fluid to the cylinder 38 on opposite sides of the piston therein, hose-connection 4! extending from the valve to one end of the cylinder and hose connections 42 extending from the valve to the otherend of the cylinder. The admission conduit to the valve is indicated at 43. The construction of the valve M and the cylinder and piston is not shown in detail as the specific construction forms no part ofthe present invention. Such presses are of well known construction. In the present instance, the press iselectrically heated, electric heating units being indicated at 43 In constructing caps in accordance with my. invention, the ends of the conductor wires are first attached to the uprights after which the uprights with the .wires attached thereto are positionedin the casing as shown in Fig. 5. Following this, the casing with the uprights thereinis mounted on the cover of the press, the cover being open 1 asshown in Fig. 2. This is accomplished by pushing the contact ends of the uprights into the openings 3! as shown in Fig.

5. In the present instance, a six cavity press is shown and accordingly six of the casings I with the uprights therein are mounted on the open cover. after the manner shown-in Fig. 2. The uprights 'fit sufiiciently tight in the openings 3! to hold the uprights in position and the uprights fit sufficiently tight in the casing to hold it in position. After the cover of the press has been loaded as shown in Fig. 2, the cover is closed as shown in Fig. 3, bringing the cap casings into the cavities 28 as illustrated. The ends of the cap casings rest on shoulders id of the cavities so that; the casings are held between the face of the cover and such shoulders, the flanges h being located in the space 30*. Also the body portions 5 of the casings fit snugly between the side walls ofthe cavities so they are firmly sup- Cylindertt is car- I ported and are in good heat conducting contact openings 30, the plug being of a size sufficient to furnish the material required for the insert.

The press is then closed bringingthe lower ends.

of the plungers 36 into the openings 30, thus forcing the material of the plugs 45 into the chambers 3 between'the inner ends of the uprights. This serves to force the material of the plugs 45 firmly around the uprights and through the openings 20, filling or substantially filling the chambers 3. The press is heated by suitable means, as for example, by steam or electricity and after the press has been closed, it is left in p the closed position a sufficient length of time for the rubber forming the insert to cure. After the rubber is cured, the press is opened and the finished plugs are removed by pulling the uprights out of the openings 3|.

By the use of this machine and method of manufacture, the caps can be quickly manufactured at low cost. One operator may operate several presses, loading one press while another press is closed, and curing the caps therein.

It will be seen that a cap embodying my invention comprises the minimum number of parts, i. e., a cap body and uprights, there being no screws required for holding the wires to the uprights or for holding the parts assembled. Also,

the wires are firmly attached to the uprights and a strain relief is provided so that connections of the wiresto the uprights is not likely to be broken. In addition, the insert holds the wires from twisting together in case the core is twisted with respect to the cap.

What I claim as new and desire to secure by LettersPatent of the United States is:

The method of manufacturing an attachment cap which comprises forming a rubber casing having a passage for a cord and an enlarged chamber at one end of the passage merging therewith and forming shoulders, mounting prong contact members having cord wires att'ached thereto in spaced relation in said chamber with said cord positioned in said passage and the inner ends of the prongs resting against said shoulders, forcing uncured rubber into the chamber between the contact members to fill it completely and embed the ends of the contact members and also into a portion of the passage to embed the wires and then vulcanizing the rubber to bond it to the walls of the chamber and passage thereby to hold the contacts in position and form a strain relief for the cord Wires.

GEORGE B. 'BENANDER. 

